This invention relates to a swash-plate compressor for use in, for example, an automobile air conditioner and, in particular, to a swash-plate compressor having an arrangement for supplying a lubricating oil to a bearing supporting a drive shaft.
A conventional swash-plate compressor of the type described comprises a compressor housing, a drive shaft extending from the outside to the inside of the compressor housing and rotatably supported by the compressor housing, a swash plate inclined in relation to the drive shaft and rotatable together with the drive shaft, and a plurality of pistons coupled to the swash plate so that the rotation of the swash plate together with the drive shaft is converted to reciprocating motion of the pistons along the drive shaft. The compressor housing comprises a cylinder housing having a front open end, a crank chamber, and a cylinder block adjacent the crank chamber, and a cylinder head mounted on the opposite end of the cylinder housing or on the opposite end of the cylinder block through a valve assembly. The cylinder block is provided with a plurality of cylinder bores in which the pistons are slidably fitted, respectively. The cylinder head is formed with a suction chamber connected to a inlet port and a discharge chamber connected to an outlet port.
Due to reciprocating motion of each of the pistons, working fluid such as a refrigerant is sucked into the corresponding one of the cylinder bores from the suction chamber through the valve assembly and compressed and discharged as a compressed gas into the discharge chamber through the valve assembly. The compressed gas is supplied to a refrigerant circuit connected to the outlet port.
The front housing has a shaft hole through which the drive shaft extends into the crank chamber. The drive shaft is rotatably supported by the front housing through a radial needle bearing mounted in the shaft hole. In the shaft hole, a shaft seal is also mounted on the drive shaft in front of the radial needle bearing so as to seal the crank chamber from the outside.
The drive shaft is also supported at is opposite ends by the cylinder block through a radial bearing.
A rotor is fixedly mounted on the drive shaft within the crank shaft and is coupled to the swash plate to rotate the swash plate together with the drive shaft. The rotor is supported on an inner surface of the front housing through a thrust needle bearing.
In the crank chamber, a lubricating oil is accumulated for lubricating moving parts of the compressor such as the bearings, coupling portions between the rotor and swash plate and between the swash plate and pistons, pistons, cylinder bores, and others. The lubricating oil is carried up by the swash plate and rotor and then splashed onto the parts in the crank chamber and the inner surfaces of the cylinder housing and the front housing. The splashed oil flows on the parts and inner surfaces to perform the lubrication.
In order to effectively lubricate the radial needle bearing within the shaft hole, the front housing has an oil path to establish communication between the crank chamber and the shaft hole. The oil flows on the inner surface of the front housing flows into the shaft hole through the oil path. The oil then insures the seal between the drive shaft and the shaft seal and also lubricates the radial needle bearing. The oil then returns into the crank chamber through the shaft hole along the drive shaft. Then the oil further lubricate the thrust needle bearing and accumulated in the crank chamber.
In the swash-plate compressor of the above-mentioned structure, the lubricating oil flowing the inner surface of the front housing is splashed radially outward by centrifugal force resulting from the rotation of the rotor. Therefore, oil is insufficiently supplied into the shaft hole. As a result, the radial needle bearing suffers insufficient lubrication and the shaft seal is not reliable in sealability. This leads to a risk of occurrence of damage of the bearing and resultant gas leakage.